Research On Synchronization For Multi-axis Motion Control Systems Based-on SoC

Multi-axis synchronization and coordination are important functions in computer numerical control (CNC) machines and multi-robot systems. Precision and efficiency on systems are impacted negatively by timing non-synchronization between multiple motion axes, system external disturbance and internal parameter perturbation, which may lead to system instability. Therefore, multi-axis motion control for system synchronization and coordination performance is an effective way to improve machining accuracy of CNC machines and running efficiency of multi-robot systems. Considering multi-axis motion control performance, this dissertation focuses on the research of timing synchronization and motion synchronization for multi-axis motion control systems. From the aspects of system platform design and control scheme, multi-axis motion control system is studied systematically to improve multi-axis synchronization performance.Firstly, the hardware architectures of multi-axis motion control systems are analyzed to investigate the influence of timing non-synchronization and delay on multi-axis synchronization. According to the analysis results, system synchronization performance depends on synchronization of sampling feedback signals, computing control algorithms and executing output modules of multi-axis motion control systems. In order to guarantee the synchronization of sampling, computing and executing, a multi-axis motion control system solution based on system-on-chip (SoC) is designed using hardware-software co-design methodology. The proposed system solution, including the architecture level and timing schedule, is used to design Zynq-7000-based multi-axis motion control system. Zynq-7000is the new generation of general SoC platform. Zynq-based multi-axis motion control system don’t only guarantee timing synchronization and functional completeness, but also improve system computing capability and integration.SoC is a complex hardware-software system integrating processor cores and programmable logic components. Efficient design and implementation plays a key role in practice for the proposed SoC-based multi-axis motion control system. With analysis of the high-level synthesis (HLS) technology, a HLS-based design method for SoC-based multi-axis motion control system is proposed to make the design and implementation easier. Then the implementation of Zynq-based multi-axis motion control system is presented in details. Resource consumption and timing analysis are discussed to verify the rationality of the proposed HLS-based design method. Experiment results are shown to test the feasibility and effectiveness of the Zynq-based multi-axis motion control system.Secondly, the proposed SoC-based multi-axis motion control system is an advanced hardware platform for synchronization control scheme research. Through a survey of general multi-axis synchronization control schemes, key issues are presented for the design of multi-axis synchronization tracking control systems and dual-axis tandem transmission control systems. The difficulty is how to improve dynamic performance and disturbance rejection performance for synchronization of multi-axis motions. To cope with these problems, a mixed H2/H∞control scheme based on state-space model is presented to guarantee dynamic performance and disturbance rejection performance for both single-axis tracking and multi-axis synchronization. With the proposed mixed H2/H∞control scheme, application cases of three-axis synchronization tracking control and dual-axis tandem transmission control are studied to propose three specific control schemes, namely mixed H2/H∞control for three-axis synchronization, mixed H2/H∞control with cross-coupling for three-axis synchronization and mixed H2/H∞control for dual-axis tandem transmission.At last, the parameter setting method for the proposed mixed H2/H∞control scheme is discussed via simulations and experiments. Performance characteristics of multi-axis synchronization tracking control are summarized with comparison and analysis of several control schemes, namely master-slaver control, tandem control, cross-coupling control, mixed H2/H∞control and mixed H2/H∞control with cross-coupling. On the other hand, simulation and experiment results prove the feasibility and flexibility of the proposed mixed H2/H∞control for dual-axis tandem transmission to implement anti-backlash and torque distribution.